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Power Question


shake777

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Where you able to look at the website I posted? Maybe that has something to do with the performance of the amp.

Cliff,

No doubt my limited electronics knowledge, but I didn't understand what it had to do with gain and magnification of preamp noise.

Another example -- hiss from a conrad-johnson amp on my CAT and K-horns just about drove me out of the room. There was very little hiss when the preamp was off.

I can not detect any noise from the preamp(Adcom GFP565). For the heck of it I just ran a test. The first audible hiss I could hear, with my ear up against the speaker, came around the 130oclock volume setting. If I sat at my listening position it was inaudible, at least to my ear. Now you have to realize that at the 130 position it would fry my fortes and most likely my chorus IIs if I was playing music at that setting.

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I can not detect any noise from the preamp(Adcom GFP565). For the heck of it I just ran a test. The first audible hiss I could hear, with my ear up against the speaker, came around the 130oclock volume setting. If I sat at my listening position it was inaudible, at least to my ear. Now you have to realize that at the 130 position it would fry my fortes and most likely my chorus IIs if I was playing music at that setting.

That's pretty darn good. We're talking past each other somewhat, partly because I didn't bulk up my posts with a lot of commentary.

VC position is irrelevant to linestage preamp noise, regardless of how far it's turned up. A VC turns up only the circuitry before it (some preamps, perhaps some Mac's, have more than one VC, but most I've seen have only one, just before the line stage.)

When you turn up your pre like you describe, you're turning the signal way up as well. In comparison, the noise itself isn't going to bug anyone. I've been talking about base preamp linestage noise, which I assess by turning the VC all the way DOWN. Then, if hiss is still too audible or interferes with softly played music, it's being magnified too much by a combination of high preamp linestage noise and/or a large amount of gain in the amplifier and/or very high speaker efficiency. That's what I've been talking about.

IME, a high-power amp spec'd at only 0.5 v input for 200 watts out, lacking any input control, and driving Klipschorns (104 db efficient) is very likely to be audible clear across the room with the VC turned way down, and will most likely be audible along with softly-played music.

Anyway, that's my only point -- very high-power high-gain amps, and K-horns or LaScalas, could well present a noise problem at rest.

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-- very high-power high-gain amps, and K-horns or LaScalas, could well present a noise problem at rest.

Exactly. My K-horns not only passed through hiss, but audible from across the room hum (120 Hz and 60 Hz), with the AV pre-amp (NAD T163) turned all the way down. Putting the AV preamp on "mute" or turning it off killed all noise, except for a slight hiss when getting close to the speakers. NAD tested the pe-amp and said it was up to spec. I solved the problem by turning the input pot on the power amps (NAD 272) down about half way (6 dB)..

By the way I never had the above problems (except for hiss very near the K-horns) with my former electronics: Luxman solid state, and McIntosh tube.

Also, I've never heard a K-horn, Belle, La Scala or speakers of similarly high efficiency (JBL theater speakers) that didn't pass through a slight hiss close up.

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  • 2 weeks later...

I had the salesman over the house and he helped me read through this thread as you would a child and helped me to understand that I could certainly benefit from more power. I also realized that I had been selectively reading to support my own bias and rationalizations. I appreciated all the time and effort the many responses required and thank you for helping me to understand this issue more clearly. That said, it will be a while before I have the means to upgrade my amps and I do still feel I'm in the range of a decent sounding system.

I am including a picture because I like pictures and coloring books, and the like. For your enjoyment as well. These two amps satisfy me at my present listening levels and can produce 110dbl or better without the sub and no clipping that I can hear. Thanks. Your time and effort reinforces my belief that this is far and away one of the best audio communities on the web. Please excuse the ratty looking nature of my cave and we have just moved and have much work and money to invest in a proper finish. Thanks again, Nic

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It would perform much better than a similarly spec'd receiver, but I'd be tempted to save up for something in the 200 wpc range. The RF-7's shine with a good amp. I'm running 300 wpc on mine.

Yes....and with any you are considering buying, be sure to look at the watts per channel rating with all channels operating. Although it is probably not at all necessary with your contemplated equipment or mine, I follow the advice McIntosh gives with their super amps (e.g., 2,000 per channel): turn on the amp (or receiver, whatever) first, wait a few moments, then turn on the rest of the equipment. Plug the system into a 20 amp circuit. I go so far as temporarily turning off anything else in the house that is on that circuit. OCD? You bet!

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First of all many thanks to Gar, Cec, and the group of members who have taken the time to help me begin to understand what, though you might not understand why, what is so difficult for me to comprehend. I just don't get numbers, clear and simple. But there is movement in the right direction as I was able to answer for the most part my own question. Truth be told I got help from my knowlegable salesman at Sixth Avenue Electronics. Now the question is what is going to be the most economical way for me to supply the correct power.? Also what are the nut and bolts of it? How many amps am I going to need? It seems like Emotiva is a good bang for the buck but what should I plan for as I begin to put together a budget. Right now it seems I'm going to presently have about one thousand and that doesn't seem like enough. So many questions but I must continue. Remember I have an 11.2 system and the RF7 speakers are running completely alone of the Denon 4306 rated at 130wpc. Those are width speakers in the Audyssey scheme. The other nine are on the 4810 rated at 140wpc. I do know these wpc numbers are greatly inflated and I do understand power under the condition of all channels operating at the same time. Thanks, Nic

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Just for starters I'm thinking two emos with 200 per five channels might do the trick. Am I on the right track? However, I'd rather wait if it means getting it right.

That would be a good option. I've read of several Reference owners who've been very pleased with the Emo's.

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I'm going to do one Emotiva five channel 200w receiver. Because of money. The big power will go to the mains the center and the the two surrounds. I'm hoping that I'm getting big power out of the 4306 if I biamp with only two channels running. It floors me that Denon insists that their amps push the advertised wattage with all channels running. This is after speaking to the supervisor. They also claim that if I biamp two channels I will get, for example, 2 X 130 for 260 watts. Remember I'm running an 11.3 system with the 4810 and the 4306. The two RF7 are running off the 4306. They are the only speakers running off the 4306. There are four channels, the two height and the two rear which may be considered as not needed big power (they have smaller bookshelf speakers, 81 and 35 besides they get less information) and will benefit from increased power when the Emotiva powers three channels off that 4810. Anyone who follows this and comments is greatly appreciated. Nic

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By the by, I understand that I could almost get the two five channel Emos with $1700.00 but I have an $1100.00 credit coming from Sixth Avenue which does not sell the Emos. This almost puts me back to ending the power quest for now and to, instead, buy a second Paradigm Sub 12, selling my remaining RT12d (or not... technically I should be discussing this in another forum section) and waiting till next Christmas for the amp(s). Sorry for so much BS but that is the corner I've painted myself into (which is not really a horrible situation). Thanks once again, Nic

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Yes, it makes the most sense to buy the sub which is the last of its kind, at a great price, and also has the sound I crave. I can always buy an amp or two later. I might have to wait till Christmas to get what I really need but it will be worth the wait. Please excuse the convouluted nature of my previous paragraph and probably at least one more. I thank you all for all your input as it really helps. Nic

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