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Audio effects board with 2x2W amp not working
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Please be positive and constructive with your questions and comments.

Re: Audio effects board with 2x2W amp not working

by joecoop on Tue Aug 11, 2020 7:18 pm

Correct. It works find when it's powered by USB. The amp is 12V so I have 12v coming in and split a 12v line to the amp and then 12V to a buck converter that outputs 5V.

The green power LED lights up and the red LED lights when I ground one of the IO pins but no sounds using Vin.

Here's what I have:
Circuit.png
Circuit.png (971.61 KiB) Viewed 25 times


The red and black wires at the top is the 12V input. I have 12V going to the amp board on the end, I also have 12V going the buck converter in the middle. From there, I have the brown and orange with 5V from the buck converter back to the board. Then I have the audio from the FX board going to the amp and the amp to the speaker.

joecoop
 
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Re: Audio effects board with 2x2W amp not working

by dastels on Tue Aug 11, 2020 8:07 pm

I'm assuming the free orange wire is connected to the convertor output to power the board.

The only thing that comes to mind is the ground. Are all ground lines solidly connected together? The only difference seems to be power source. And it seems to be working (you get a red light when triggering) ... just no audio. Do you have a way to connect headphones to L/R? It should drive headphones without an amp. If you get sound out that way, it would give us more information (i.e. some power related connection to the amp... my bet would be the ground).

Dave

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Re: Audio effects board with 2x2W amp not working

by joecoop on Tue Aug 11, 2020 8:20 pm

Correct. The free orange wire is the 5V+ and the brown is 5V- from the buck converter. I verified that I am getting 5V.

I'll try the headphone but it's strange that everything works through the amp when I'm connected to USB power. I may just solder wires the the 2 usb power pins and be done with it.

joecoop
 
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Re: Audio effects board with 2x2W amp not working

by dastels on Tue Aug 11, 2020 8:55 pm

Agreed, it's odd. Grounding issues can cause odd problems.

dastels
 
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Re: Audio effects board with 2x2W amp not working

by joecoop on Wed Aug 12, 2020 2:14 pm

After much trial and error, I finally got it working! First I tried soldering wires to the 5V pads on the USB port and trying that. Same results. I then tried a powered speaker. That worked which narrowed it down to the amplifier. I tested with a different amp and it worked. I had another amp the same as the original and didn't work! So, I tried using the L and R pins instead of the L and GND. That worked! Not sure why and not sure why it worked with everything except that amp but the problem has been resolved.

Thank you for your help!

joecoop
 
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Re: Audio effects board with 2x2W amp not working

by dastels on Wed Aug 12, 2020 3:20 pm

Odd that L & R worked. But really all the amp looks at is the different between it's two input lines (it sort of assumes one of ground (i.e. a 0 reference). But it works! Huzzah!

Dave

dastels
 
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Re: Audio effects board with 2x2W amp not working

by joecoop on Wed Aug 26, 2020 3:09 pm

So now I have another problem. I had the header pins soldered to the bottom to use in the breadboard and everything worked. I desoldered the header and moved it to the top and the board stopped working. The green light comes on but the computer doesn't recognize the board. I figured it was something with the desoldering so I bought another board and started with the header on top. All good for a while. I have changed anything but now it doesn't work. The green led lights. Nothing happens when I ground a pin and the computer doesn't see the board. I also noticed that on both boards, the chip next to the usb connector gets hot. Maybe that's normal. Not sure where to go from here. I don't want to buy another board.

joecoop
 
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Re: Audio effects board with 2x2W amp not working

by dastels on Wed Aug 26, 2020 3:20 pm

Frustrating. The sounds won't trigger while It's connected to USB. But why it doesn't show up... I'll do some research.

Dave

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Please be positive and constructive with your questions and comments.