how much power do you need two drive magnpan1.6s

My MG1.6 sounded best when driven with a 600 watt (4 ohm) digital amp. CarverPro ZR1600. They sound almost as good with the audiophile-approved CI D200, also digital, and good for 350 watts.

Maggies can sound deceptively good with much lower power, but you won't know what you are missing.

Magfan...Its Voltage squared divided by ohms load.

70 volts would be 1225 watts.

I actually made some measurements while my MG1.6 was playing very very loud music. My objective was to see if my 600 watt amp was overkill. I saw peak voltage at a level that would correspond to an amp of about 600 watts. Of course, at more moderate SPL and during most of the music the voltage peak level was more like 12 or 14 watts. Based on my findings I decided that 350 watt CI D200 amps would be OK, and I applied the ZR1600s to other tasks. By the way, my experiment was done with the Maggies seeing only 50Hz and up.

Rockadanny...I simply used a digital voltmeter, which makes a measurement about once per second. Careful observation will yield a result very near the maximum brief rms voltage. Then the peak is reasonably estimated as 1.4 times the rms. A peak-reading meter would be better, and an oscilloscope would be best.

Magfan...True that Watts = E * I,

But I = E/R

So Watts = E * E / R.

Also, the "rail" voltages get output one at a time. PlusV-to-ground OR MinusV-to-ground. Never PlusV to MinusV.

Also, the 4 amp fuse is at 120 volts. It can yield much greater current at the lower voltage delivered to the speaker via the amplifier.

Magfan...Stop and think about what I said. Sometimes the voltage at the hot (red) terminal of your amp may be +70, and sometimes it may be -70 but the black terminal is always 0, so the speaker never sees more than 70 volts across it.

80 volts applied to a 4 ohm Maggie would result in 20 amps (assuming the amp could deliver this). The power would be 1600 watts, so it better not be applied very long!

At 120 volts 1600 watts is 13.33 amps. If course no amp is 100 percent efficient, so the 120 volt line fuse would need to be a higher value. If, however, you had an amp running on 240 volt power, 1600 watts would necessitate only 6.67 amps plus some for amp inefficiency.

4 amps at 120 volts represents 480 watts. For simplicity let's assume the amp is 100 percent efficient. If you had a speaker with a 1 ohm impedance 22 volts would be 480 watts. The current drawn would be 22 amps (and all from that 4 amp fuse in the 120 volt line).

Your remarks about fuse voltage ratings makes no sense. I never said anything about fuse voltage rating. The voltage rating exists to protect against arcing after the fuse blows which might occur if the voltage is greater than the fuse rating.

Magfan...If we use 6 ohms (as you do) I agree with your 400 watts. However, I was under the impression that MG1.6 were a pretty flat 4 ohms, and resistive to boot. Using 4 ohms and your 50 volts gives 625 watts.

A fuse blows because of I*R heating. Voltage doesn't matter. How long it takes to blow a fuse depends on how high the current is. The rating of a fuse, eg: 4 amps, is the current it will carry forever without blowing. Most fuses actually carry about 1.2 times their rating for quite a while, and twice their rating briefly. "Fast blow" and "Slow blow" fuse types are designed to modify these typical characteristics.

I have some experience with really, really, realy, fast fuses! They were to protect transistors in a very expensive and hard to repair motor drive circuit in a missile guidance system. Turns out, there are fuses that are fast enough to protect transistors, but they are themselves transistors, and they cost more than what they protect. It was worthwhile in this case to use the fuses because the cost to repair a blown circuit, reassemble and retest the guidance system would have run to tens of thousands of dollars. Better to replace the thousand dollar fuse.

Magfan...Interesting about the impedance plot of the MG1.6.

I did an upgrade to the crossovers in my MG1.6...same design just better parts, like air core inductors. I was surprised to find that the high and low frequency crossover slopes were not only different, but the crossover frequencies were significantly different also. I seem to remember that the LF was electrically rolled off well below where the HF cuts in, and this would result in an impedance increase through the gap. Magnepan does a lot of proprietary tweeking to achieve flat frequency response, and the crossover design is part of it.

This is why I have serious doubts about the wisdom of biamping Maggies using an electronic crossover.