I took on the challenge of building my own amplifier, with 0 knowledge on what I'm doing ( no joke, but I know you want to laugh 
. My build consists of a 25 -0- 25 650va toroid and two yuan jing 150w x2 amp boards to make a 4 channel amplifier. Where I am at noe after so much back and forth is that with no inputs plugged in the amp is dead silent. Once my inputs are plugged in I get ground loop buzz, but I can't find the loop. I am attaching pictures to see if anyone might be able to spot the problem, or my just have some words of wisdom. Thank you!
. My build consists of a 25 -0- 25 650va toroid and two yuan jing 150w x2 amp boards to make a 4 channel amplifier. Where I am at noe after so much back and forth is that with no inputs plugged in the amp is dead silent. Once my inputs are plugged in I get ground loop buzz, but I can't find the loop. I am attaching pictures to see if anyone might be able to spot the problem, or my just have some words of wisdom. Thank you!Attachments
For someone claiming to have "0 knowledge on what I'm doing", I have seen much worse.
A few questions:
"Dead silent" with no inputs plugged in" does that mean you have the impression the amplifier does not work?
Have you tried the amplifier with the headphone output from your SmartPhone (floating in potential)?
Where did you ground your chassis?
Have you checked with a voltmeter that the supply voltages on the two amplifier boards are correct?
A few questions:
"Dead silent" with no inputs plugged in" does that mean you have the impression the amplifier does not work?
Have you tried the amplifier with the headphone output from your SmartPhone (floating in potential)?
Where did you ground your chassis?
Have you checked with a voltmeter that the supply voltages on the two amplifier boards are correct?
I did a star ground on a piece of the chassis that extends up and stops vibration from the top cover. It is metal and mounted firmly to the chassis, it is pictured in the middle pic. I only have the toroid, the main power plug, and the amplifier grounds grounded together. Do I ground the shielding of the inputs to the star ground also?
So with amp on and phone used as source. I plugged it into each input and I get no buzz! I haven't tried that yet, but it was nice to hear clear music with no buzz. The source I am trying to get to work is my computer. I make music and the amp powers my monitors. The chain of music signal goes; computer to presonus firebox through firewire, then from the firebox out of the main left right outputs it goes to a minidsp that has two inputs and four outputs that run to the four inputs of my amp. It is so frustrating I can't get it to not buzz.
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