amp efficiency

[dmz2711 10+ year member]

Is there a way to determine the efficiency of an amp??? I know the typical numbers are around 60% for an A/B class amp, and 80% for a D class amp, but how do you figure the precicse efficiency of an amp out???//content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

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[JimJ 5,000+ posts]

Determine how much power is being drawn compared to the amount of power on the output //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Requires some bench testing supplies, an accurate ammeter, scope, etc.

 

[bigbassman Premium Member]

(power out / power in) * 100 = efficiency

at the bare minimum, you'll need a clamp ampmeter, and a digital multimeter

use a test tone...

measure voltage and current going into the amp

example 12.8 volts, 148 amps

P = VI so 12.8 * 148 = 1894.4 watts of power into the amp

do the same on the output end..

example 42 volts 28 amps

P = VI 42 * 28 = 1176 watts coming out...

plug it into the formula up above

(1176 / 1894.4) * 100 = 62.07% efficient

by knowing voltage and current coming out of the amp, you can find the actual impedence for that frequency

R = V/I so 42 / 28 = 1.5 ohm

Loyd L.

 

[dmz2711 10+ year member]

(power out / power in) * 100 = efficiency
at the bare minimum, you'll need a clamp ampmeter, and a digital multimeter

use a test tone...

measure voltage and current going into the amp

example 12.8 volts, 148 amps

P = VI so 12.8 * 148 = 1894.4 watts of power into the amp

do the same on the output end..

example 42 volts 28 amps

P = VI 42 * 28 = 1176 watts coming out...

plug it into the formula up above

(1176 / 1894.4) * 100 = 62.07% efficient

by knowing voltage and current coming out of the amp, you can find the actual impedence for that frequency

R = V/I so 42 / 28 = 1.5 ohm

Loyd L.

thanks so much!!! i got it all except when you say output and input what do you mean??? where do i measure output and input???//content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

 

[bigbassman Premium Member]

input... power & ground...

output.. the speaker leads..

Loyd L.

 

[dmz2711 10+ year member]

input... power & ground...
output.. the speaker leads..

Loyd L.

thanks again i really appreciate it!//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif