# Can I connect aux-out straight to the amp?



## tangcla (Nov 12, 2010)

I'm sorry if this question is dumb. But no question is dumb 

Can I connect the RCA aux-out from something, to the amp RCA inputs?


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## Eljosh (Sep 29, 2010)

I would think so, but I have wondered the same


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## t3sn4f2 (Jan 3, 2007)

Depends. What exactly are you referring to by an Aux out? What device and connections on it specifically?


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## sqshoestring (Jun 19, 2007)

I was into this years ago for marine systems but I forget half of it. You can do it and people test amps all the time that way, just patch your ipod/mp3 into the amp....but you can run into problems so I recommend you use something as a head it does not have to be a head unit/deck some EQs or line drivers work. Most personal players have a weak output and you have to gain the amp way up, and you can have noise issues in a car, or it might work fine it depends. Some of the marine guys use the broadcast units and play it through the radio, so when they tie up everyone can play the same music. Others get a HU that works the menu on an ipod and with a remote for the dash then hide the HU inside. You might find good info on marine sites, because hitting waves with a CD player has never worked out that well solid state music is where its at.

It is common to input home CD players/etc into car amps when testing them inside, of course you need something with a volume knob if you don't use the amp's gain. But home equipment is spec'd at 1v output or something.


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## j sexton (Sep 19, 2009)

I have a ppi eq i use ,to play music through my phone straight to amp,I get sub control and all. but I have run it straight to amp ,with gain at 3/4 so i could test subs in the comfort of my room,works fine .used a 3,5mm headphone jack to rca adapter.


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## sqshoestring (Jun 19, 2007)

You can get some really cheap EQs now, some even have SD card slots and USB ports as well as aux jacks....but I don't know about the quality of them.


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## tangcla (Nov 12, 2010)

RCA aux-out from an Alpine TME-M740 screen. I'll be using an RCA splitter (as a joiner) on one or two channels, to combine with my headunit input (Alpine IVA-W520E).


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## t3sn4f2 (Jan 3, 2007)

tangcla said:


> RCA aux-out from an Alpine TME-M740 screen.* I'll be using an RCA splitter (as a joiner)* on one or two channels, to combine with my headunit input (Alpine IVA-W520E).


That's a big no no. 

Why Not Wye?


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## tangcla (Nov 12, 2010)

Is it really that bad?


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## t3sn4f2 (Jan 3, 2007)

Can't say, I'm no expert in that topic. Rane on the other hand, if anyone is, they are.

Let me understand correctly though. You want to combine two source output pairs into one input pair of one amp? Can't you use a source selector switching device?


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## tangcla (Nov 12, 2010)

I might have to look into one. I want one to always output and broadcast, as it'll be the nav voice.


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## t3sn4f2 (Jan 3, 2007)

tangcla said:


> I might have to look into one. I want one to always output and broadcast, as it'll be the nav voice.


That could be a tough one. You might need to purchase some type of signal summing module that is used to recombine crossed over signals from a common source.

Something like a JL Audio CL-SSI. I'm not sure if it can correctly combine full range inputs like you need done though.


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## sqshoestring (Jun 19, 2007)

You can make a summing Y with resistors, its posted here and other places. Maybe at bcae1.com. Could put a pot on it to adjust one to level them if needed. That way each source drives into the resistors, they each have a load.


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## tangcla (Nov 12, 2010)

Is there anyone with some electronics knowledge able to build one for me? 
Happy to reimburse costs, of course.


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## sqshoestring (Jun 19, 2007)

I'm not sure how it will work, here is one thread saying 600 ohm resistors will work and provide a mixed signal not summed. This works fine for sub out because most bass is pretty much mono anyway, but not sure on highs. For real summed it would be easier to buy something that did it if you are not into electronics, I don't know how to setup op amps either lol.
summing rca's... - diyAudio

All you have to do is get a couple resistors for each channel, put one on the center of both inputs, tie together, run that out to your amp. The shield should cover all of it. If you had a metal box you could run the RCA into it, cut them, connect the shields to the box, put the resistors on the centers, run the single pair of RCA out the other side with that shield attached to the box also...the box would shield the entire thing. Or you could cheat and do it inline in the RCA, insulate the resistors, and wrap the outside with foil/etc as the shield, then tape it all up or wrap it.


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## tangcla (Nov 12, 2010)

sqshoestring said:


> For real summed it would be easier to buy something that did it if you are not into electronics, I don't know how to setup op amps either lol.


Thanks - I have a basic understanding of electronics, but allow me to emphasise basic, and I definitely do not enough to risk blowing up equipment 

I would buy it off the shelf, but I can't seem to find something that would do what I want... Happy to be proven wrong though


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## sqshoestring (Jun 19, 2007)

Some old MTX amps do it so you can connect a sub amp, and they are full range out. Pretty sure I have a 4ch that does that it sums the front and rear. Kinda large to drop an amp in to do it, but I don't know what else aside from some kind of processor/EQ/etc there are a ton of those out there seems like one would be able to do it not sure. I don't think the resistors deal would blow anything up. However it might not be the right levels you may have to adjust, it could maybe screw up the sound such that when one got loud the other got quieter or something like that. The two signals might fight each other a little, but with resistors it should not damage anything...its low resistance that might that is why you don't want to connect two sources with no resistors, this way they both have at least 600 ohms that is enough to be safe is my understanding actually 100 likely is.


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## tangcla (Nov 12, 2010)

So what's the correlation between RCA input voltage and resistance/impedance?


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## Ludemandan (Jul 13, 2005)

You could switch inputs using one of these. PAC AS-21 2 Channel Audio Switcher

It's meant for an automatic switch, so it requires a trigger signal. If you want to do it manually, you might be able to find a 2-position toggle switch that has four poles, and route the positive RCA leads through each pole so only one or the other input can be connected.


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## tangcla (Nov 12, 2010)

Ludemandan said:


> You could switch inputs using one of these. PAC AS-21 2 Channel Audio Switcher


I have seen that on the PAC website, however I do want both inputs to mix through and play together - the AC-21 cuts one to play another.



Ludemandan said:


> It's meant for an automatic switch, so it requires a trigger signal. If you want to do it manually, you might be able to find a 2-position toggle switch that has four poles, and route the positive RCA leads through each pole so only one or the other input can be connected.


Sorry, don't understand this part. 
edit: I don't think I want it to be switched manually, in fact I don't think I want it switched at all


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