12V Trigger Question

Thread Starter

BPet

Joined Oct 30, 2017
22
I'm using the Scosche LOC2SL Line Output Converter to connect the speaker output from my Whole Home Amplifier into a second Amplifier to power outdoor speakers. So, the LOC2SL converts the speaker level signal down to an RCA Left/Right Line Level Signal that can be used as an input into the Amp. The Scosche LOC2SL also has the ability to send a 12V trigger to the amplifier so that the amp only turns on when music is playing.

My issue:
Besides the wires to connect the speaker signal input and the RCA outputs to go from the LOC2SL to the Amp, the LOC2SL unit has a yellow wire to accept 12V+ as input, a blue wire to send 12V+ out to trigger the amp, and a black wire to connect to ground. The LOCSL (Line Output Converter) is designed to be used in a car and so the directions indicate that the Black ground wire should be connected to the car chassis.

The outdoor speaker amplifier, a Monoprice Unity 100, has a 3.5mm jack as an input to accept a 12V trigger to turn the amplifier on.

I plan to use a wall wart 12V DC adapter to provide power to the LOC2SL and then use the LOC2SL to trigger the outdoor speaker amplifier. I can strip the end of the wire on the 12V DC adapter, but it will have 2 wires and so how would I connect that to the 12V+ Yellow Wire of the LOC2SL? Also, the LOC2SL has a single Blue wire for the 12V+ output and so how would I convert that to a 3.5mm plug to connect to the Monoprice Unity 100 3.5mm jack - usually the cable with a 3.5mm plug would have 2 wires in it, not just a single wire?

Thanks in advance for any help that you can provide! :)
 

crutschow

Joined Mar 14, 2008
23,141
Connect the +12V of the adapter to the 12V+ Yellow Wire of the LOC2SL.
The -12V of the adapter is the same as the vehicle chassis so connect that to the black wire.
Connect the Blue wire to the center terminal of the 3.5mm jack and the -12V (connected to black wire) to the outer terminal of the 3.5mm jack.
 

Thread Starter

BPet

Joined Oct 30, 2017
22
Connect the +12V of the adapter to the 12V+ Yellow Wire of the LOC2SL.
The -12V of the adapter is the same as the vehicle chassis so connect that to the black wire.
Connect the Blue wire to the center terminal of the 3.5mm jack and the -12V (connected to black wire) to the outer terminal of the 3.5mm jack.
Thanks crutschow!

Almost there:
turns out that, if I connect the Negative from the DC Source, the LOC2SL, and the 3.5mm plug heading to the Amp, and then the DC Source to the Input on the LOC2SL and the 12V output from the LOC2SL to the 3.5mm plug headingg to the Amp, it "kindof" works. When I turn the audio source on, the Amp does not turn on - BUT if I continue to increase the volume of the audio source, the Amp's LED starts to go from Red(standby) to flickery green...the higher I turn the volume, the more solid the green light, but it is still not enough to turn the amp on. I measured with a volt meter and it fluctuates between .2 and 1.1V. If I remove the ground from the 3.5mm plug and measure between that ground and the hot side of the plug, I get 6V, but it does not change whether the music source is on or off?

The source speaker output cable is approx. 60ft long, and then it goes into a volume controlled switchbox, and so maybe the signal is too weak at that point to allow the LOC2SL to use it's trigger function?

Looking to tap my speaker wire and use a device to activate a 12V trigger when the music is on.

I Found a PAC TR-4.
https://pac-audio.com/catalog/specialty-items/tr-4

So, the volts to trip the trigger come from taping the speaker + wire. The speaker wire originates from my Whole Home Amplifier that is in the family room and the speakers are on the back patio and so that is where I will tap the wire. I'm planning to put a second amplifier outside and so the 12V trigger output on the TR-4 will turn on that amp. The TR-4 also has a lead for 12V+ input (which will come from a DC Power Adapter), 12V+ output(which will go to the Outside Amp trigger input), and a Ground lead.


The TR-4 is usually used in a car and the Ground would go to the car chassis - since I'm not using it in a car, where would the Ground Wire connect? I would think the Ground would be connected to the Negative wire on the DC Power Source. But how would the TR-4 Measure the Volts on the speaker Tap if it only has the + side of the circuit? Or should the Ground of the TR-4 be connected to the Negative side of the speaker wire?

Thanks in advance for any advice! :)
 
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