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Josh, I understand, but it's confusing for folks when you mention an implied equivalence between SS amplifiers and tube amplifiers of half the power. It's much more complicated than that. Soft-clipping is distortion.....regardless of how benevolent its audible effects. That violates the "all other things being equal" proviso. Cheers,Dave.
Then there is the fact that tubes reproduce all of the harmonics (in Triode), whereas SS doesn't. It is amazing how more detail there is in Triode which I listen in about half of the time. Jim
Josh:My point is that if it is inaudible, it is a non-sequitur. As you know, output tubes sound their best when saturated, just before they start to compress the highs. With my system this happens right at 99 to 101db c weighted in fast mode which is very loud. This equates to transient peaks near 110db. I listen typically at around 95db which is still very loud, well under the compressing point and still with plenty of headroom. 60 watts of tube power from my old Jolida 502 crapped out on my 1.6's to the point where I would get panel slap and serious sibilance (overly compressed highs). I can only surmise that the Jolida had a less than hearty power supply. In triode mode in my Marantz's, I have no problem driving the 2.5's into the low to mid 90's without ill effects, reason, beefy power supply. It is not just about the wattage but about the total topology and ability to drive a 4 ohm or lower load. This is a fact no matter if the amp is SS or Tube. Jim
Sure, technically it isn't even solid state vs. tube, the difference here is that tube amps can only have so much NFB, hence their soft clipping characteristics.And certainly with Maggies you have to be able to drive a 4 ohm load without frying the amp.The power supply also matters, as you point out. An amp that doesn't recover quickly from clipping will sound worse when stressed. It's silly, but the weight of an amp can tell you something about how conservative the design is. It isn't unusual to find that two amps with the same published power specs will have very different performance because one has a hefty power supply, a big filter bank, and high current capability.It isn't really possible with the specs that are available for the typical audiophile amp to know just how loud it will play before sounding distorted with actual program material. Hell, even if you could, nobody sets volume controls with perfect precision, room acoustics vary, etc. So when I figure the size of an amp, I allow some extra headroom. But if you're dealing with tubes where power is expensive, that may not be a suitable strategy. Then I think the thing to do is take some measurements, use those to get a ballpark figure, and then try it.
From what I remember from a few friends that had them, anything capable of some current. Minimum were the Adcom amplifiers. Bryston, big HK integrated amps (like the PM665) and such.
Okay guys, I guess you folks did not understood my last post: "capable of producing some current". Obviously this is not a quality of sound consideration, but again I am/was assuming you folks would understand the relationship between power, current and the ability to drive a particular impedance.I:= V/R and P:= I²R, P:=V²/RIf the impedance drops to 1/2 of a given value for R (well actually Z if formally correct), and V is constant, P must go up if an ideal device. Implied is that if I increases, then R(Z) decreases for a given voltage.
Maybe I'm missing something, because I assume everyone here knows that.
Well it seems as though the discussion was going the way of impedance rather than a discussion concerning current. A high current amp will be able to drive a lower impedance than a lower current capable amp, all else being equal. This is completely in agreement with Jim Winey and Magnepan. Unless I completely mis-read the responses or other posts, in which case please ignore my last post.stew
I've got the answer:The BEST amp is the one you can't afford.
Me2 I think one of the few things that can be done regarding the impedance of loudspeakers is the addition of a Zobel or similar device. A varying impedance cannot be eliminated, but it can be minimized. Now the problem with adding any device between the amplifier and loudspeaker (or in parallel as need be) is the relative inefficiency of these devices and the power requirements to voltage drop across these devices. Why can't we have our cake and eat it too?
I guess I'm just not seeing the problem with driving these kinds of loads. The speakers are relatively insensitive at a Stereophile guesstimated 83dB/1watt/meter. Magnepan sensitivity measurement reflects the 4ohm nature of the speaker in that when fed 2.83 volts twice the current will be drawn from the amplifier which results in an 86dB sensitivity rating. That being said I still don't see them as a power hog. 10watts in gives 93dB@1 meter, 100watts is 103dB @ 1meter. In as much as they are line sources they don't fall down with distance the way a point source does. Scotty
No, they're easy loads (though I agree with Davey -- the best approach with any speaker is to put the crossover ahead of the amps). The speakers are on the inefficient side, though. You do gain a bit from the 1/R radiation pattern of the full height ones but you also lose room gain because of dipole cancellation. Per your figures, you'll need a 100 watt amp to listen at moderate levels, a big one to listen at realistic ones, e.g., a minimum of 115 dB peaks (which most audiophiles don't, so no bother for most). So that's what some people complain about. Really, it isn't a problem if you're cool with solid state, since big, economical, high quality solid state amps are available. But people who want to use SET amps will find little joy.Wendell points out BTW that it would cost more to increase efficiency by using neodynium magnets than it does to get a bigger amp if you need high levels.It's easy to see though how the misapprehension that Maggies don't play loud occurs, if you go to a dealer and turn it up to see what it will do and the dealer has a 100 or 200 watt amp on it well it will peter out. The same audiophile might be happy with a 200 watt amp at home, since he doesn't normally listen at those levels.
