# Common ground for subwoofer-out

I have a Sony Sony DSX-A110u which is a car stereo having 4*55W Speaker out and a Sub-woofer out. The subwoofer-out port it a female RCA jack. which looks like this

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I am using the sub-woofer out jack to feed in a another stereo-subwoofer amplifier which takes in 3 wires Left, Right & Ground as a input

I have given input to the other amp. like this

## THE PROBLEM

As you can see the car's stereo subwoofer output both channel separatel via RCA jack so naturally, To give input to my other amplifier, I joined the ground pin of RCA cables to make it 3-pin stereo format.

Now the problem is, As soon as I join the ground wire of the both RCA out, The volume output of other subwoofer amp gets really low and makes a Tick-Tick noise once every second, Like some digital signal has been passed with the audio signal. Its more noticeable in higher volumes.

The tick-tick noise continues even when nothing is playing on the stereo.

The amplifier works fine in MONO mode otherwise! (Using just 1 RCA jack)

## Can anyone tell why this is happening and what can I do to fix it?

• @dandavis the other amp I am using is 5200 1943 Mosfet amp and it is having a 3-pin input in form a a 3.5mm female jack. In this case what I can do? – GeekWithGlasses May 28 '20 at 21:06
• That will be a workaround but not a solution. I already mentioned in question that mono works fine. Also, if there's two jack, which clearly says L - R that means its stereo and I know many songs which have bass line on only one channel. it will make a difference and It won't give optimal listening experience. – GeekWithGlasses May 28 '20 at 21:29
• @GeekWithGlasses it will not make a difference. Physically, bass is so low-frequent, that it makes no difference whether your sub is left or right. The wavelengths, compared to the space between your ears, means that you can't tell the direction the bass comes from – unless you're a sperm whale or something bigger. In which case: kudos for your ability to participate on this platform! But even then, a bass amp just muxes bass to a mono channel, because it's optimized for humans, sorry. – Marcus Müller May 28 '20 at 21:34
• "The subwoofer-out port it a female RCA jack" - er, no,it isn't. This unit doesn't have a subwoofer output. The two RCA connectors are for the rear channels. – Finbarr May 28 '20 at 21:53
• @dandavis Check the manual, the larger black one on the left is for the antenna, the blue one on the right is for remote control. The sub label is presumably for another model that shares the same casting but has more holes drilled. – Finbarr May 29 '20 at 16:53