gagelle Posted June 16, 2011 Share Posted June 16, 2011 I thought I understood power ratings until recently. Years ago when I obsessively read "High Fidelity" magazine, the rule was to look for something that was rated RMS with both channels driven. There were many units on the market that did not really have high fidelity sound. They not only had inflated power ratings but other important measurements were not listed. The great thing about most Klipsch speakers is that they're very efficient. This is a tremendous advantage as one does not have to spend a fortune for a high powered amplifier. I'm into vintage Sansui receivers. It seems like the crowd is mainly focused on high powered models and they consequently have been bid up to very high prices. But there are many low powered models, that in many cases, have a sweeter sound than the monster power units. And with Klipsch speakers they can produce enough volume to damage ones hearing. The lesson I've learned recently is that there is a wide variation in the quality of sound produced by particular amplifiers. I was supprised when I purchased my first home theater receiver which had fairly high power ratings. The sound quality, however, was terrible, even when driving only two speakers. I've since read many complaints about this issue. The units process video, have HDMI ports all over the place, upconvert, connect to the internet and much more. The trouble is that they sound like a transistor radio when played through high quality speakers. Bring in the sub woofer because the amp was made to power tiny speakers with no low end. The home theater trip has been an education for me. It seems like you need big bucks for big sound. I've slowly moved back to two channel. And I was lucky enough to discover Klipsch speakers. Who knows, one day I may go to tubes. Quote Link to comment Share on other sites More sharing options...
KanedaK Posted June 16, 2011 Share Posted June 16, 2011 Eventually you will notice that everything in an amplifier has a tremendous importance for the resulting sound quality: quality of the composants, quality of the connection, internal layout, quality of the case and chassis... A typical home-theater receiver has a very different purpose and suffers from everything non-audio it has to include in the same box, plus nasty digital processings, and not to mention it has to be done for less money than your typical Hi-fi amplifier. Not surprisingly, those amps fail to deliver real music. Quote Link to comment Share on other sites More sharing options...
JJkizak Posted June 16, 2011 Share Posted June 16, 2011 My older Denon stereo AVR rated at 55 watts per channel blows away my newer Denon 7.1 AVR rated at 110 watts per channel. This suggests to me that the newer Denon is actually closer to 20 watts per channel, strictly by ear of course. JJK Quote Link to comment Share on other sites More sharing options...
Don Richard Posted June 16, 2011 Share Posted June 16, 2011 Home stereo amplifiers since the 1970s have to be rated by the Federal Trade Commision method. This is a very rigorous testing protocol that includes a one hour preconditioning period at 1/3 rated power before measurements are made, with both channels driven simultaneously. Home theater and autosound equipment are not required to be tested in that manner. Usually HT recievers do not have enough power supply to supply all it's channels at once. So yes, there are different power rating methods applied to 2 channel gear versus HT, with the 2 ch being more "honestly" rated. Quote Link to comment Share on other sites More sharing options...
Cal Blacksmith Posted June 16, 2011 Share Posted June 16, 2011 High power is not need for sure but high QUALITY is! I would guess that nearly all of my listening is under 1 watt of power. My 2ch setup is all tube driven and has a rated output of 55 wpc. My HT setup has a Yamaha AVR that is rated at 110wpc all 7 ch driven but I really doubt that it could come close to that. I have it seperated so that my mains are driven by a pretty good quality 2 ch stereo amp, a Fort'e 3, and this takes the load off of the AVR to give better quality sound to the entire system. It made a huge difference, just breaking off the mains from the amp. The sides, rears and center now have enough power to do their job and still sound good, even with very efficent Klipsch speakers in all 7 positions. Quote Link to comment Share on other sites More sharing options...
gagelle Posted June 16, 2011 Author Share Posted June 16, 2011 Very interesting Don. This is something I did not know. Quote Link to comment Share on other sites More sharing options...
gagelle Posted June 16, 2011 Author Share Posted June 16, 2011 I did the same thing. I bought an Emotiva 3 channel Amp for my front speakers and it has made a tremendous difference in sound quality. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted June 16, 2011 Share Posted June 16, 2011 I did the same thing. I bought an Emotiva 3 channel Amp for my front speakers and it has made a tremendous difference in sound quality. This makes me think of what I will do next. I am 90% done building my first of 4 subs which will run nicely on 200 watts or less RMS. The Emotiva amps would drive them well. I was going to buy two Behringer A500 amps for $500, but now I am thinking about the Emotiva unit for $800. I am looking at these Emotiva 5 channel amps, and I am liking what I see. Thoughts? Quote Link to comment Share on other sites More sharing options...
Boxx Posted June 16, 2011 Share Posted June 16, 2011 Home stereo amplifiers since the 1970s have to be rated by the Federal Trade Commision method. This is a very rigorous testing protocol that includes a one hour preconditioning period at 1/3 rated power before measurements are made, with both channels driven simultaneously. Home theater and autosound equipment are not required to be tested in that manner. Usually HT recievers do not have enough power supply to supply all it's channels at once. So yes, there are different power rating methods applied to 2 channel gear versus HT, with the 2 ch being more "honestly" rated. Very well said Don... Thanks... Quote Link to comment Share on other sites More sharing options...
Cal Blacksmith Posted June 17, 2011 Share Posted June 17, 2011 I did the same thing. I bought an Emotiva 3 channel Amp for my front speakers and it has made a tremendous difference in sound quality. This makes me think of what I will do next. I am 90% done building my first of 4 Bill Fitzmaurice Tuba Home Theater (THT), which will run nicely on 200 watts or less RMS. The Emotiva amps would drive them well. I was going to buy two Behringer A500 amps for $500, but now I am thinking about the Emotiva unit for $800. I am looking at these Emotiva 5 channel amps, and I am liking what I see. Thoughts? You asked lol! I tend to like the older stereo equipment VS newer all in one type amps, in part for the testing methods as outlined above. Used high quality stereo amps are quite a deal when compared to the WIZZ BANG high end HT stuff. There are many great stereo power amps that are going unloved in today's HI-TECH "magnolia room" HT stores environment. Sure 4 stereo amps or 7 mono amps will take up a lot more room (or even like I have, one AVR plus a stereo amp for the mains) but with careful choice and a little shopping, I think they will sound MUCH better. Hey ya asked for thoughts and those are mine. YMMV! Quote Link to comment Share on other sites More sharing options...
gjones11 Posted June 17, 2011 Share Posted June 17, 2011 You are exactly right about no need for high power with high efficiency Klipsch. I have a set Cornwall I speakers, all original (I am original owner). When I matched them up to a low power McIntosh MC2275 (only 75 watts/ch), wow, what a sound. My amp runs about 10 watts and plenty load. But using an all tube amp into the Cornwalls is the answer for me. Quote Link to comment Share on other sites More sharing options...
JJkizak Posted June 17, 2011 Share Posted June 17, 2011 The AVR power ratings seem to be based on measuring the system at 3:00 am on the Greenland icecap with ice packed into the receiver on January 31st. JJK Quote Link to comment Share on other sites More sharing options...
gagelle Posted June 19, 2011 Author Share Posted June 19, 2011 Something interesting I came across is that in the rush toward mass marketing, over the last ten years or so, manufacturers have been using cheap elactrolytic capacitors in a race to increase profit margins. In some cases, these capacitors are faulty from the factory. (See Wilipedia article on "electrolytic capacitor plague." There has lately also been a serious problem with bootleg transistors, some from reliable companies. Quote Link to comment Share on other sites More sharing options...
cornfedksboy Posted June 22, 2011 Share Posted June 22, 2011 Packing all those amps into a congested package meant to reach the mass market really constricts the amps ability to do it's job. I bought an Onkyo with pre-outs with the specific intent of hooking up an amp to drive the fronts. The power rating for avrs is based on 1 channel driven, so a 7.1 channel 100 watt amp delivers 100 watts at the maximum permissable distortion ratio to ONE channel. Each channel you add will decrease the output of the amps by 5-10%. With that in mind, the 7 channel avr will only deliver 50-75 wpc with 5 channels driven. In addition, the avrs will generally use an inferior capacitor (as mentioned above) to those of the seperate amps. For these reasons, HT enthusiasts will usually go with a pre-amp/processor in combination with seperate ampliphiers. For instance, you wouldn't use an ampliphier/turntable combo to drive a Hi-Fi system. Quote Link to comment Share on other sites More sharing options...
fini Posted June 22, 2011 Share Posted June 22, 2011 Eventually you will notice that everything in an amplifier has a tremendous importance for the resulting sound quality: quality of the composants, quality of the connection, internal layout, quality of the case and chassis... Don't forget (as our friend Mark Deneen, or any other designer might add) the circuit! Quote Link to comment Share on other sites More sharing options...
gagelle Posted July 7, 2011 Author Share Posted July 7, 2011 I found an article the other day on a Denon receiver that had a real 100 RMS power rating with 7 channels driven at the same time into 8 ohms. Each channel had its own power supply and circuit board. I don't think it's still made but it's a monster weighing over 70 pounds. This article gave an good explanation for some of the low power ratings for home theater receivers. This Denon could pull nearly 10 amps, close to the maximum that should come from a single wall outlet. Imagine how many people would buy a receiver if they were informed that they would need to call in an electrician before hooking it up? Another thing mentioned in the article that I didn't know, is that there's only one state which requires audio equipment to have UL certification. Quote Link to comment Share on other sites More sharing options...
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