Kurt, I salute you on asking your question instead of making an assumption. First, a minor clarification. Your Gem's have an efficiency of 87 dB for one watt input at one meter. They have a "nominal" impedance of 6 ohms, and a minimum impedance of 4 ohms. In other words, they are of pretty much average efficiency and a little more difficult load than average, but no sweat for an amp in the league of Levinson or Ayre or Pass. Amplifier power for stereo amplifiers is customarily per channel, unless otherwise specified. Thus, your "125 watt" Levinson amp is 125 watts per channel, and so on. The question of how much power is enough depends more on your listening tastes and room. For example, say you like orchestral music at the kind of volume you'd get halfway back in a concert hall, maybe 95 dB peaks. And, let's say you sit 12 feet from your speakers. We're going to ignore some factors to make this simple. Okay, one of your speakers will give you 87 dB at 3 feet (one meter, give or take). Two of them, each getting one watt input, will give you 93 dB at three feet. Back up to 12 feet, and the sound pressure level will have fallen off to 87 dB. This is fairly loud, but remember we want peaks of 95 dB. Now here comes the important part. When we increase the wattage input by a factor of ten, we increase the sound pressure level by ten decibels. So at 10 watts per channel input we get 97 dB at our listening chair, at 100 watts input we get 107 dB, and at 1000 watts input we get 117 dB. So you can see that a 15 watt tube amp would give us our 95 dB. I'd like a bit more reserve power for occasional forays into hard rock, but I'd rather have 15 real good watts than 1500 crummy ones. Of the amplifier brands you mention, the Pass Aleph series would be my first choice. Hope this helps.

A "dumb" question about power ratings?

I'm no engineer, but I believe that our Revel Gem speakers have an impedance of 87db, which is whiy the dealers I talk with to recommend an amplifier that puts out at least 100 watts. If this is correct, does this mean that they are suggesting 100 TOTAL watts? Here's where I'm a little confused: The solid state amps I've looked at like the Levinson 334 or Ayre V-1 are "rated" in terms of total watts available. In this example 125 watts and 200 watts respectively. If that's right, then 1/2 of the total wattage is available to each speaker. A 200 watt amp provides about 100 watt per speaker - right? The reason I ask is that mono-block tube amps and the Pass 'class A' amps seem to be rated by the watts put out by each mono unit. If a mono-block tube amp is rated at 50 watts, then that means 50 watts for each speaker, or the equivalent of 100 total watts available in the system -- is this correct? Put simply, is a mono-block tube amp rated at 60 watts roughtly equal in power to a solid state amp rated at 120 watts? I find power ratings and figuring out how much amplifier power is optimum a bit confusing. I suspect this may be a dumb question, but I just want to make sure I understand the ratings correctly. Also, I'd love to know how to make the decision of how much power is enough. Is it simply a mathematical question dependent on how loud you want the speakers to play? Or do other sonic factors come into play? I've read about tube amps that only put out 15 watts, which seems miniscule to me. Would my Revel Gems even operate running off a low powered tube amp? What would they sound like? This is America, after all, isn't more power always better :-)? I will certainly appreciate your insights! Sincerely, Kurt

8 responses Add your response