How to add second amp

[Noko]

I have a JL XD400, I think, 5 channel amp running 4 speakers and a sub. I'd like to add two more speakers mid boat by the captain's seat and the other side. How do I add another amp to power the two new speakers? I put in a new HU which I believe puts out 75 or 50 W/channel. I was thinking of just running the new speakers off the HU. My existing amp doesn't have any output RCA plugs. I thought I could also split the RCA inputs between amps if that would work if I put in another 2 channel amp to run the new speakers.

 

[Inthrustwetrust]

How many RCA outs does the head unit have? I would just use a RCA splitter if you don’t have another. For the positive/neg/remote I would just wire to the same spots as your original amp. If you do a lot of floating you might need a bigger battery. And if you don’t already get a tender.

 

[Noko]

How many RCA outs does the head unit have? I would just use a RCA splitter if you don’t have another. For the positive/neg/remote I would just wire to the same spots as your original amp. If you do a lot of floating you might need a bigger battery. And if you don’t already get a tender.

Splitter was what I was thinking from looking at ways to do the split. HU has 4 RCAs, front. back to the amp

 

[212s]

Splitter was what I was thinking from looking at ways to do the split. HU has 4 RCAs, front. back to the amp

You have three choices:
You can split it with a Y adapter. Or you can use one set of RCA's from the head unit for the new amp. You should be able to set the JL amp into 2ch mode so it only needs one set of RCA's. Don't bother with the head unit to power the speakers, you'll be very disappointed with the output - use an amp to drive the extra speakers.
Or simply connect the extra speakers to your current JL amp in parallel to drive 4 speakers on one set of channels.

I'm running 8 speakers off my JL 4ch amp in parallel and it works great.