new amplifier

[MDS]

Nice job, Eric. Your post #116 should be made a sticky as it summarizes the relevant issues quite nicely IMO.

 

[jaxter]

Headroom

Eric,
Nicely stated in both cases. Music is dynamic and since power requirements go up in a logrithmic fashion it is easy to see why 500 or even 1000 watts would not be unreasonable to reach the peaks in many recorded movies or music without any compression.
Your steady state requirements would be relatively low most of the time, 2-5 watts for most systems, but when that peak comes through you can run out of power very quickly. Especially in cases like the recent War of the Worlds film. The DTS track on this can rip your head off if your system is capable of it. From a reference level of 85 dB, I would suspect that this film can get up to somewhere around 105 dB. I havn't measured it but I was listening to it with some 90 dB sensitive speakers (seven in total), through a Lexicon LX 7 amplifier (200 RMS w/ch) and two JBL HB 5000 subs (800 watt 15") and it could make you flinch even when you knew what was coming.
Room 24x20x9::

 

[Nick250]

When the quick snap of some hand claps (sounds like finger snaps or something) hit in the source material the scope showed about 75 volts p-p, or (75/2)^2/4 = 352 peak watts.

So that backup power really does matter, it's extreamlly short duration I observered here at about .5ms (.0005 seconds). But, none the less that much power was required to avoid clipping.

I am not being a smart ***, my question is serious. Given sufficient power, would a .5 ms spike be audible and/or would a speaker be able respond to such a brief spike? Intuitively, to me it seems unlikely, but that's all I have, intuition.

 

[mtrycrafts]

That to me really does say a big amp (or more sensitive speakers) has it's advantages when playing highly dynamic sources and you wish to enjoy music composed of mostly quiet passages at a nice level. ...

Of course, this all ignores the fact that a lot of recievers rated at 125 WPC into 8 ohms have rather aniemic power supplies that fold quickly and can't peak at over 350 watts into 4 ohms (even for a few ms) like the outlaw I measured. In that case, bigger looks even better.

Or, my math could be completely wrong...

Your math is not wrong. Some of the assumptions may be.
What peak level you want to achieve at the listening position would be my first question. How sensitive is the speaker, what impedance and how much spl is needed at 1m to satisfy your peaks. What is the dynamic headroom of the current amp.

If your speaker is 4 ohms, of course you cannot expect most 125 watt amps to peak 350 watts into 4 ohms.

 

[mulester7]

.....don't think "peak" watts when everything is most strained....think continuous....a large pool of continuous, that's clean.....

 

[Eric Apple]

I am not being a smart ***, my question is serious. Given sufficient power, would a .5 ms spike be audible and/or would a speaker be able respond to such a brief spike? Intuitively, to me it seems unlikely, but that's all I have, intuition.

Actually, I recall just looking at half the wave form so the entire waveform period was double that, or 1 ms. That equates to 1 khz. But, it was actually more likely a higher frequency that appears for that duration.

Can I hear it ? Well yes, you can clearly hear the sound in the music. Sounds about as fast as the snap of one those little tear drop shapped tissue wrapped fire cracker things you throw on the cement and they pop, or a cap pistol. (Just guessing here...I don't think my timing is very accurate at 1ms!!!)

Can I hear if there was distortion? I would say yes if it was a sine wave, but that is not much fun the listen to. Since BEP is all about distortion anyhow, it would have to be alot before you noticed anything strange sounding.

 

[mtrycrafts]

Actually, I recall just looking at half the wave form so the entire waveform period was double that, or 1 ms. That equates to 1 khz. But, it was actually more likely a higher frequency that appears for that duration.

Can I hear it ? Well yes, you can clearly hear the sound in the music. Sounds about as fast as the snap of one those little tear drop shapped tissue wrapped fire cracker things you throw on the cement and they pop, or a cap pistol. (Just guessing here...I don't think my timing is very accurate at 1ms!!!)

Can I hear if there was distortion? I would say yes if it was a sine wave, but that is not much fun the listen to. Since BEP is all about distortion anyhow, it would have to be alot before you noticed anything strange sounding.

But are we hearing that .5 or 1 ms burst or the after effects that follow? Want if you just have a .5/1ms burst with nothing else? How about masking issues?

 

[Eric Apple]

But are we hearing that .5 or 1 ms burst or the after effects that follow? Want if you just have a .5/1ms burst with nothing else? How about masking issues?

Mtry I don't know the answer to that question. My guess is that you would hear the leading edge waveform from the speaker, and then any ringing in the speaker along with decay in the room. The recording limits of CD are within the range of human hearing, so I think anything that could be recorded on CD could be heard at least by some people.

 

[frankf]

I have looked into thr Rotel and Cary amplifiers. I cannot find a dealer in my area that carries them. Comparing Rotel and the Outlaw was fun and it was easy to make a decession as to which one I would purchase. Rotel and Outlaws' specs were very similar and in some cases Outlaws were better. Rotel pricing were more that I wanted to spend. Outlaw is coming out with two new amplifiers soon the 7500 and the 7700 5&7 channels amps. I am going to try to find a dealer who carries Cary. I will probably will have to travel some distance. Thanks

 

[frankf]

Thanks

I have looked into thr Rotel and Cary amplifiers. I cannot find a dealer in my area that carries them. Comparing Rotel and the Outlaw was fun and it was easy to make a decession as to which one I would purchase. Rotel and Outlaws' specs were very similar and in some cases Outlaws were better. Rotel pricing were more that I wanted to spend. Outlaw is coming out with two new amplifiers soon the 7500 and the 7700 5&7 channels amps. I am going to try to find a dealer who carries Cary. I will probably will have to travel some distance. Thanks

I have not been on line for some time. it has been a long process to make a decision about what amplifier to buy and whether or not to use my Yamaha 3300 receiver as a processor.
With the votes tallying up outlaw wins hand down. Build quality, sound and price not to mention all of the accolades that I have read about the company and the products. It is a no brainer. I was so confused with all that is out their and the obvious was looking at me right in the face. I am a audio & video enthusiasts however I do not know how some of you guys understand and keep up with all of the changes in electronics, my hat goes off to all of you. At the time I first wrote in, with all of my questions, questions, questions the 7700 was not available only the 7500. Since that time the 7700 has come in and it is a fantastic piece of equipment.
That's my baby. The idea of getting the 990 processor is bitter and sweet. Bitter because I really thought that I was going to carry the yamaha 3300 receiver as the processor. Yamaha's notible processing unit is top rate.
The decesion came after listening to my friends Yamaha and his Anthem amp for some time and when he purchased his Anthem processor there I heard a hell of a difference. The sweetness is in the 990.
So come June at the HT show in LA I intend to take my baby home. The problem is how do I get this monster home here on the east coast? Anybody, any ideas? I do not intend to store it in with the rest of the baggage. No way!! I intend to ask if I can put it in the closet of the aircraft. Maybe they will be nice that day. I work for the airlines so maybe that will be an asset. Who knows? I definitely need some kind of carrier for that amplifier. My friend should have no problem with the 990.
Another change is that I intend to purchase Definitives' BPX2's. I have there 1.2s' and they do a great job but only rated at 150 watts. The 2s' are rated at 200 watts. I know that I will probably never have that amp. cranked up using all 200 watts plus, but I want to feel comfortable and have some give and take with those rears. I am also replacing my Definitive subwoofer (PF1500) with a smaller sub giving me more room in my HT since the wife and I deceided to rearrange the room a bit so we can add a couple of more sits.
In conclusion I want to thank anybody and everybody who gave me advice and direction with this thread.
Also if you are interested you might see my PF1500 and my BPX1.2's on audioholics.
Thanks again, and COME ON JUNE!!!!

Definitive 2004’s mains
Definitive Clr2001 center
Definitive BPX1.2’s surrounds
Definitive BPX1.2 center rear
Definitive PF 1500 sub-woofer
Infocus 7205 projector
Da-lite 0 gain screen
Comcast HD Digital Box
Monster 3500 surge protector
Monster 3600 surge protector
Yamaha 3300 receiver
Toshiba 5 disc DVD,CD player
Sony 777 DVD, CD player
Pioneer Elite Laser disc player
Pioneer Elite Cd player
Marantz RC 5000 remote
Mit & Monster cables

 

[ZoFo]

The 7700 is a 100 lb Amp!

The last thing I would want to do would be to haul that thing around the airport and on a plane. It was not easy getting the 7700 from my truck to the bottom shelf of my rack by myself, and I am talking about 50 feet. It really takes TWO people to move an Amp this size, even a few inches. I cannot see them letting you carry this onboard and I would not want to check it as bagage although I have "checked" a few $20,000 Servers before. The difference was I did not pay for the Servers out of my pocket and there was no other choice. Why are you buying it in LA when you live on the East Coast? Even if you can fly for free I received my Amp three days after I ordered it from Outlaw. The 900 does not weigh much but it is a very large Pre/Pro, as big as they come and it's double-boxed which adds to it's size making it too big for cary-on. I would have them ship it direct, and also get the package deal for $200 less.

I am sure you are going to love the 990 / 7700 combo; mine has been great.

 

[mulester7]

The decision came after listening to my friends Yamaha and his Anthem amp for some time, and when he purchased his Anthem processor, there I heard a hell of a difference. The sweetness is in the 990.

.....standing ovation....hope your plans work out great....

 

[highfihoney]

i have noticed while i was in the market for an amplifier that it is not for the reasons of having more power to blow my remaining hearing away, it definitely enhances and gives more definition in sound. some things you did not hear before. i just wanted to have an idea of what people out there besides salesman are thinking.
hopefully by next week i will be putting some pictures that i have of my home theater room on this forum. thanks again to everyone!
rubbersoul662001

hi frank,for the record on this whole messy & misunderstood issue i own both reciever & slave amps & i love them both,i have nothing to gain from bashing my own reciever or its capabilities but ive yet to see any reciever do what a quality power amplifier can & will do for alot of systems,my 270 wpc reciever cant even come close to the performance of my 200 wpc seperate amplifier.

the path that your currently undertaking in upgrading your systems performance is where many of us started out (including myself) it started for me wanting a true stereo bass response that my reciever simply wasnt able to give(bass with balls from my mains),i added a seperate power amplifier & i heard a dramatic difference in bass response,the music had more depth & the best benifit was that after adding the seperate amplifier the overall clarity in the sound increased by leaps & bounds,i heard these differences many years ago & i still hear them today.

from my experience the more you seperate all your gear by running seperate amps & preamps the more you will gain in sound quality,shared transformers are not good for the best sound available,room treatments,speaker efficiency,spl's & all that jazz are incentidential issues that have very little to do with the quality of the signal that your speakers are seeing,CRUD IN CRUD OUT.

before you listen to anybodies advice(from either side of the camp) on this subject go to your local guitar center store & buy a 200 watt slave amp to demo in your own home,they offer a no questions asked money back on the spot gaurentee,i would also question anybody giving advice as to what their personal experiences with seperate preamplification & amplification is.

all this stuff that is continuously brought up about not needing amplifiers to be able to play at ear bleeding levels is utter nonsense,loudness is rarely the issue for people who want better sound/performance from their systems,i myself have heard the differences & i will never go back to systems designed to do many things at once.

 

[eirepaul]

well said highfihoney, and thoroughly agreed!!