Command HU Output
09-05-2011, 10:26 AM
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2004 C240 4Matic
I am looking for Continuous Watts per Channel RMS. I know the Bose ones use a separate amp but non Bose do not and power the speakers. I was curious what the spec's of the head unit itself was.
09-05-2011, 11:21 AM
#4
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most car HU have standard bridged output power amp ICs. the one in my audio10 is from philips is TDA8569Q. There is only so much you can get out of 12 volts. It is rated at 15watts at 0.5% distortion or 21 watts at 10% distortion TYPICAL with 13.2 volts DC
up to 35 watts at 30% distortion with 14.4 volts.
up to 35 watts at 30% distortion with 14.4 volts.
09-08-2011, 03:36 AM
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2005 C Wagon (No snickering please!)
The onboard amp for the head unit is a class B (meh) with a bridge tied load. They rate it as 4 X 40 watts, but that is not a real world figure. First the maximum device dissipation is 60W. Assume a 90% efficiency that is 54 watts available to four speakers at 2 ohms.
I measured the power in a vehicle sending pink noise to a single channel. It started to clip at 12 watts into the speaker. A 2 ohm non-inductive load remained clean up to 13 watts.
Stairway to Heaven was too loud at 8 watts per speaker, all four channels driven. Yo-Yo Ma's Suite for Solo Cello No. 1 in G Major, BWV 1007: I. Prélude, was good at 8 watts, clipped at nine, and was unlistenable at that and above.
The engineers that did the thermal work on the headunit must have completed their work in the wintertime because driving all four channels with a 440/6800 cross mod signal at 12 watts caused the unit to exceed the 150 C junction temperature limit.
I measured the power in a vehicle sending pink noise to a single channel. It started to clip at 12 watts into the speaker. A 2 ohm non-inductive load remained clean up to 13 watts.
Stairway to Heaven was too loud at 8 watts per speaker, all four channels driven. Yo-Yo Ma's Suite for Solo Cello No. 1 in G Major, BWV 1007: I. Prélude, was good at 8 watts, clipped at nine, and was unlistenable at that and above.
The engineers that did the thermal work on the headunit must have completed their work in the wintertime because driving all four channels with a 440/6800 cross mod signal at 12 watts caused the unit to exceed the 150 C junction temperature limit.
