HsvToolFool: Nobody puts 300+ watts of power through a speaker.
Rich: Do you necessarily need 300 wpc or more to drive the Summits? No.
If both of your answers converge to "
NO", then would a 150wpc amplifier from the same manufacturer be a better fit? For example, if Krell had a 150 wpc "FPB150", would this 'baby Krell' be a better amp for the Summits than the FPB300? Let's even the playing field by saying that both Krells are made using the exact same power-supplies, except that the baby Krell has less output devices. If the answer is
YES, the baby Krell will sound the same, then why have all the extra output devices? Would they be '
wasted'? If your answer is
NO, then that means you really need the FPB300 to drive the Summits in order to give you the desired sonic signature. Does this contradict with your statement that you don't need 300wpc for the Summits? I'd venture to say that given this scenario, the baby Krell may sound better than the bigger brother just due to the fact that there are much less components in the signal chain to mess up the output signal. If you want to keep all parameters as close as possible, do try to listen to the legendary Krell KSA-50 or KSA-100 and compare with the newer FPB series.
I have two words for you: Dynamic Headroom.
Is it helpful to have that headroom for a neutral and accurate presentation of the musical signal? Absolutely.
Ok, let's do some real measurements here, shall we? I'll use my "less-than-efficient" ReQuest panels for these calculations. My ReQuests are rated at 90db, and we all know the ReQuest panels are a couple of generations older than the X-Stat of the Summits. Theoretically, with 32 watts on tap, I should be able to get 105db from 1 speaker at 1 meter. I confirmed the measurement using my RadShack SPL meter this morning. 105db+ out of 1 speaker, driven strictly by one 50watt SixPac monobloc. It's also interesting to note here that at my listening position 12-feet away (4 meters), the same speaker gives 101db+ reading. Only -4db drop due to the ReQuest being a line-source rather than point-source. So, with 2 speakers going, I registered 104db+ on my SPL from the pair of SixPacs alone! Also keep in mind that the SixPacs are driving the panels AND the woofers for this exercise, while the Summits have the internal bass amplifiers, reducing the toll on the amps driving them. I don't know about you guys, but 104db is plenty loud for me and I was able to get there with a pair of 50-watt monoblocs. So, I failed to see how "headroom" becomes a factor in this specific scenario or how a 300wpc amp can provide more headroom over the SixPacs.
Oh WAIT, but I DO have a 300wpc amp laying around! Let's do some more measurements, shall we? New configuration: ML ReQuests driven full-range by Classe' CA-300 @ 300wpc. I registered 112db+ and it was VERY uncomfortable. I'd NEVER want to even come anywhere close to this level. I'm pretty sure the CA-300 has more to go but I'd never use it.
But wait a minute, I just happen to have its little brother, the Classe' CA-150 also! Why not put it through the paces? Another configuration: ML ReQuests driven full-range by Classe' CA-150 @ 150wpc. I also got 112db on the RadShack SPL at my listening position.
So, what have we learned? Strictly speaking number-wise, the 150wpc will push the limits of your ears and the extra devices are wasted in the bigger amp. But in reality, the bigger amplifier has a much better power-supply circuitry and better quality components making the sound more 'effortless' when comparing the Classe' brothers. The SixPacs have huge power-supplies but that's another story by itself. So, the trick is to find an amplifier with good power-supply impelementation, but with the minimum number of components to serve your need. THAT is very hard to do!
For my ears which max out around 99db before pain sets in, 50watts for the panels are more than enough and I still have some headroom left to go.
I have 130 wpc of tube power driving the panels on my Ascents. Could I get by with just 30 wpc? Sure.
I spent a couple weeks with the ARC VT100 (100wpc) in my system, comparing it with the SixPacs and found that the ARC gave hints of running out of steam when pushed. The midrange hardened and the highs becamed edgy. But the SixPacs at half the wattage rating didn't seem to break a sweat! Go figure.
You also seem to infer that watts per channel is the only spec that matters with these amps. And since they put out so many watts, they are wasted on the Summits. Give me a break.
No, you missed my point. Watts-per-channel is only an indication that there are more devices in the signal chain to mess things up. If you don't need those devices to begin with, then why have them in the signal chain to distort your signal at all? Remember that an amplifying device makes a copy of the original signal and output this copied signal to the next stage. The original signal is thrown away. Following this rationale, the copy of a copy of a copy is never as good as the original. You ALWAYS lose something during the copy of analog signal and this is EXACTLY what we're talking about. And we have not even started on the noise issue, noise putting onto the signal path from each device in the chain. So, keeping the number of copies and the number of components to the minimum is a good thing in my book.
I can't imagine too many people that wouldn't be happy with the result, except for a few that are so stuck on the sound of tubes that they wouldn't consider any solid-state amp for Logans.
For this post, it's strictly about numbers and engineering practice. I have left out the tube-vs-solid-state or any other personal preferences. Let's just agree to disagree on those fronts.
Cheers,
Spike