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By ryurkovich

I have a couple simple questions about hooking up the STA540 Audio Amp to an MP3 Trigger board.

1. Power: Can both amp and board be hooked up to the same power source? Ex. Both positives, one from mp3 trigger, one from amp, and both negatives hooked up to same place.

2. Audio: For hooking up left and right speakers, its clear what to connect. What isn't clear is what to do with the Audio GND spot on the MP3 Trigger board? does this need to get connected to something on the amp if using stereo audio?

By ryurkovich
Oh, yes I see where I may have confused you.
I am not hooking up the speakers directly to the mp3 board
I read the MP3 Trigger hookup guide, but could not find anything about hooking up an amp. The speakers I'll be using will be hooked up to the amp, which will be hooked up to the MP3 Trigger board.

So going from the MP3 Trigger board to the Amp, does the Audio Ground connect to both negative inputs on the Amp?
User avatar
By DanV
I'm pretty sure you use the audio out jack to go to the amplifier.

Don't solder anything to those pads on the board.
Those pads on the board are for jumpering to select headphone or line-out.
If you need separate RCA plugs for your amp, then split the cable and send to ground to both of the plugs.
Last edited by DanV on Wed Aug 01, 2018 12:21 pm, edited 1 time in total.
By ryurkovich

Is there a way to convert the two potentiometers that control the left and right volume of the amplifier to one knob that pans from left to right?
So that when the knob is in the center position its playing both left and right equally?
By ryurkovich
Aha, thanks. Do you think I would need to get one with a different Ohms? The ones I was using for the separate left and right knobs were 10 ohms.
Would I need to connect the top and bottom row of connectors on the 2-gang potentiometer?
I don't think they're available with different ohms top and bottom.
10 Ohms?? most volume knob style pots likely start at 1K if not 10K ...
no, connecting top and bottom would defeat the purpose of having 2 pots - I mean they're separate pots, just mechanically linked - if you're using 2 pots now, then these 2 (ganged) pots would substitute in for them, wired somewhat separately and all.
By ryurkovich
An issue has started with this setup.
It was working fine until we installed it, and something came loose and the speakers are making a fast heartbeat loud thumping sound.
I switched out all the components and its still doing it. Could I possibly have wired something wrong?

I'm using an MP3 Trigger with the SparkFun Audio Amplifier Kit - STA540.
Power supply: AC/DC Switching Adapter Output 12V , 1000mA
Potentiometer (double) 2W 10K
Speakers (2) 5W 8 ohm