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Old 4th September 2016, 03:28 AM   #1
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Default New ACA Build Low Power and Noise

I just built the ACA kit and using the switching supplies the power is only about a watt and the noise is 26mV on the scope. I tried the amp with my linear regulated supply and the noise is 12mV and the power is 6 watts. I let the amp burn in for 30 minutes and I set Q1 to 10V. Has any one else had this problem? Thanks
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Old 4th September 2016, 09:27 AM   #2
Zen Mod is offline Zen Mod  Serbia
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Iq in ballpark ?

is PSU voltage steady ?

just use other switching supply
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Old 4th September 2016, 11:40 AM   #3
xrk971 is offline xrk971  United States
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Add 33mF (or 22mF) 0.47Rx4 33mF CRC in between your SMPS and amp should knock it way down (if SMPS doesn't choke on turn on in-rush). Precharge the caps first with 10R power resistor between SMPS and first cap. EThen use manual switch to enable full current after a minute.

If you want to know it down even more to 1mV level add a split core 0.56mH and and another 33mF cap for CRCLC.

Last edited by xrk971; 4th September 2016 at 11:46 AM.
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Old 4th September 2016, 05:52 PM   #4
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The amplifier works great from a linear power supply, there is no voltage sag on the switching supply. The inrush current is not a factor. The model of the power supply is: PPP014S. Has anyone else had a problem like this with this supply?
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Old 4th September 2016, 06:39 PM   #5
Zen Mod is offline Zen Mod  Serbia
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dilemma is simple to solve - use other switcher supply

take it as black box , (which probably is, anyway) , it's either good or not
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