A little deeper on amp power please....
If somebody could elaborate on exactly how a higher watt amp will improve the sound of speakers (lower sensitivity speakers that “need” power). More specifically, I get that when the nature of the recording and the volume setting demand an immediate spike in power, an amp that delivers the spike will perform better than one that does not. But when I used to have an amp with output meters, it would be in single digits for most normal listening, and I don’t recall what a spike would have been - I want to say 15 or 20 watts. What I am scratching at is whether there is something more to power, i.e. the notion that the effortless power of, say, a 300 watt amp would somehow be an improvement over an otherwise similar 75 watt amp…even if a spike is just 20 watts. Hope the question make sense.
There are some megabuck Class A amps I can't stand to listen to for more than a few minutes at a time, while I've never had a problem listening to ICEpower, so I could see some truth in this. |
All these years and you still assume I'm typing in the least informed context, @atmasphere , give me a little credit? I meant to say, being forced to now give an exhaustive/exhausting answer: Our search for amps that are rated high into 8 Ohms may actually be a search for load invariant amps, that can sustain the voltage even as the impedance drops and the phase angle varies from resistive. The modern day equivalent of the Krell KSA 50 (50w/channel into 8 Ohms) which was low rated power but able to drive 1 Ohm loads is a rare find indeed. |
I think that in addition to power, there's the issue of feedback vs. output impedance. By using massive output stages (relatively) you reduce the need for feedback to achieve low distortion. This tends to only work with high power amps, but surely not all of them. I suspect that a lot of what we think of as the need for power is really the need for high current, and that with ideal 75-100WPC amps with many output devices and low feedback we'd be very happy. |
I think the reality is a little complicated, but you are right that most of us never exceed 20 Watts listening. I think it may best be explained that some speakers are a lot harder to drive than you would think, and an amp that can handle them without sagging tends to be bigger, heavier and higher power. By sagging I mean both reduced overall output but also changes in frequency response. That is, the ideal amplifier would output the same frequency response regardless of speaker, but as we get further and further from ideal the amplifier’s output tends to start to mirror the speaker impedance, even at low listening volumes. One of the best sources of information about this are the Stereophile amplifier reviews. Take a look at the measurements where they test with a simulated speaker load, and pick a few tube amps vs. a few solid state amps and you'll start to see a pattern. |
