I would guess that in the vicinity of 100w/ch to 8 ohms is something of the sweet spot. The best blend of
Quality/Money/Power. A good ~100w/ch to 8 ohms amp will drive all but the most difficult speakers.
Personally, I think for 140w speakers costing $500/pr, a 350w/ch amp is a bit of overkill. Though if you can afford it, 200w/ch to 8 ohms wouldn't be out of the question. But in reality, ~100w/ch to 8 ohms would be sufficient.
There is a legal standard for representing the power on Hi-Fi amps set by the Federal Trade Commission. That standard is a full range frequency sweep to an 8 ohm load. This is so all amps can be fairly compared.
4 ohm power rating of an amp is something of an illusion. The limiting factors for an amp is headroom or voltage ceiling. Simply drawing more current and thereby drawing more power does not raise that voltage ceiling. For a 100w/ch amp, the voltage rails are about 45 volts. And that voltage is not linear, as there is a Square factor to power. So, calculating the RMS voltage for 50w is about 20 volts. However, 100w is only 8 volts more at 28v. Small changes in voltage equal huge changes in power.
Though some will argue the point, the quality of the watts
(actually the amp) makes a difference. There are high end amps with modest power that drive very strongly, and there are low end amps with seeming high power that don't drive all that well.
I suspect the 100w/ch in this amp -
Yamaha R-S202 - 100w/ch - $150 -
http://www.crutchfield.com/p_022RS202/Yamaha-R-S202.html?tp=47041
will not hold up as well as the 100w/ch in this amp -
Yamaha AS701 - 100w/ch - $800 -
http://www.crutchfield.com/p_022AS701S/Yamaha-A-S701-Silver.html?tp=34948
So, when you run 4 ohm speakers, you don't really have more power, rather you are simply consuming more current which results in more power being consumed. But the amp is still limited by the power supply voltage rails; that doesn't change, and if it does change, it goes down.
The
Peachtree Audio Nova 150, has
150w/ch to 8 ohms and cost in the $1500 to $1600 price range. That's more than enough. While the Nova 150 does have a DAC, there other full featured amps that you could consider. If that amp, the features, and the price appeal to you, then it should be more than enough.
But I think we need a clear statement of budget?
Here is an alternative. If you want Amps with ever climbing power and an ever climbing price tag, check this link -
Post
#5 -
http://www.avsforum.com/forum/173-2...g-2-channel-amp-suggestions.html#post45697625
You need to determine the features you want, and draw the line at a particular price, then see what is available at that price.
Myself, I would love to have the
Parasound P5 Pre-Amp combined with the Parasound A23 (125w/ch) Power Amp ($2090).
Using the
Parasound A23 as an example,
125w/ch to 8 ohms translates to
225w/ch to 4 ohms. So you can see any 80w/ch to 100w/ch, assuming good quality, is not going to have a problem with the ELAC speakers.
Again, simply illustrating 8 ohm power vs 4 ohm power, the
Yamaha AS501 is rated at 85w/ch to 8 ohms and about 120w/ch to 4 ohms.
So, you really don't need a crazy amp. I'm guessing anything between 60w/ch and 100w/ch to 8 ohms is more than enough. Depending on how sanely you use your system, I really can't see any need for anything over 100w/ch to 8 ohms.
The
Elac Uni-Fi UB5 has a -
maximum power input: 140 watts - implying that any good amp between 50w and 150w would have no problem driving it, assuming a reasonable standard in an amp.
The limiting factor is your budget, and the list of features you need. Assuming enough budget, there are many reasonably high power amps to choose from.
One last word of advise, relating to available Power -
It is never over-powered or under-powered amps that destroy speakers; it is always the guy running the Volume Control. Don't be that guy.
Steve/bluewizard