Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Have questions about a SparkFun product or board? This is the place to be.

Moderators: phalanx, TS-Tim

Post Reply
ryurkovich
Posts: 17
Joined: Wed Mar 28, 2018 7:46 am

Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by ryurkovich » Wed Aug 01, 2018 7:33 am

Hello,

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?

Thanks,
Rachel

User avatar
DanV
Posts: 365
Joined: Sat Apr 25, 2015 9:29 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by DanV » Wed Aug 01, 2018 8:39 am

You really MUST read the hookup guide:
https://learn.sparkfun.com/tutorials/mp ... -guide-v24
Right and Left do NOT go to speakers!
That device is head phone -OR- line out to an external audio system (not both) but NOT speakers.
Those pads on the board are for jumpering to select headphone or line-out.

ryurkovich
Posts: 17
Joined: Wed Mar 28, 2018 7:46 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by ryurkovich » Wed Aug 01, 2018 8:54 am

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
DanV
Posts: 365
Joined: Sat Apr 25, 2015 9:29 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by DanV » Wed Aug 01, 2018 12:16 pm

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.

ryurkovich
Posts: 17
Joined: Wed Mar 28, 2018 7:46 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by ryurkovich » Wed Aug 01, 2018 12:20 pm

I have used those lines out before to hook up to a mono amplifier. It worked with the Left attached to + and the Ground attached to - on the amp.

ryurkovich
Posts: 17
Joined: Wed Mar 28, 2018 7:46 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by ryurkovich » Fri Aug 10, 2018 11:28 am

NEW QUESTION

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?

User avatar
DanV
Posts: 365
Joined: Sat Apr 25, 2015 9:29 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by DanV » Fri Aug 10, 2018 12:21 pm

There are 2-gang potentiometers available - I don't know if you would need linear taper as opposed to audio taper.
just wire each gang opposite of the other - one is decreasing as the other is increasing.

ryurkovich
Posts: 17
Joined: Wed Mar 28, 2018 7:46 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by ryurkovich » Fri Aug 10, 2018 12:25 pm

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?

User avatar
DanV
Posts: 365
Joined: Sat Apr 25, 2015 9:29 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by DanV » Fri Aug 10, 2018 2:12 pm

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.

ryurkovich
Posts: 17
Joined: Wed Mar 28, 2018 7:46 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by ryurkovich » Sat Aug 11, 2018 7:14 am

Sorry I forgot the K in the 10k. 10K ohms!
What I meant was Should I get a 2-gang pot with higher ohms than 10k

User avatar
DanV
Posts: 365
Joined: Sat Apr 25, 2015 9:29 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by DanV » Mon Aug 13, 2018 8:47 am

If 10K is OK now then stick with 10K

ryurkovich
Posts: 17
Joined: Wed Mar 28, 2018 7:46 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by ryurkovich » Mon Sep 17, 2018 7:56 am

Hello,
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

ryurkovich
Posts: 17
Joined: Wed Mar 28, 2018 7:46 am

Re: Hooking up Audio Amp Kit STA540 to MP3 Trigger Board?

Post by ryurkovich » Mon Sep 17, 2018 8:47 am

When I'm able to get the thumping sound to stop, theres still a muffled deep noise thats not supposed to be there when panned to the left speaker

Post Reply