How to know what voltage reading to aim for?
Volts = sqroot of {watts ( rms) x load ( ohms )}
say for example you got an amp that is rated at 50wmrs per channel @ 4ohms,
then
Volts = sqroot { 50wrms x 4 ohms }
= sqroot {50x4}
= sqroot {200}
= 14.14 volts
if you are setting gains on a sub woofer you can use the following 50 Hz test tone, rest of the procedure remains the same..
50Hz 0db.mp3 - File Shared from Box.net - Free Online File Storage
lets say you got a 600wrms @ 2 ohms rated amplifier, play the 50Hz track and aim for
Volts = sqroot {600 x 2}
= sqroot {1200}
= 34.64 volts.
If you are bridging 2 ch on an amp for powering a sub, simply double the voltage reading... how??
lets see.. say we got a 2 ch class A/B amp rated like this
a - 100wrms x 2 @ 4ohm stereo
b - 200wrms x 2 @ 2 ohms stereo
c - 400wrms x 1 @ 4 ohms bridged
Va = sqroot {100wrms x 4ohms} = sqroot {400}= 20 volts ( stereo )
Vb =sqroot {200wrms x 2ohms} = sqroot {400}= 20 volts ( stereo )
Vc = sqroot {400wrms x 4ohms} = sqroot {1600}= 40 volts ( bridged )
20volts setting in stereo mode, where as 40volts setting in bridged mode... most class A/B are stable only at 4 ohms in bridged mode.. so simply double the voltage you aim for...
a lot of people trust their ears, but it depends on how trained your ears are at differentiating between clean and clipped signals.
the above technique is a fool proof technical method to set the gains on your amplifier, JUST RIGHT. |
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