Rca Question

[Space Goat]

ok im running two amps, one for each sub how do i connect them both to the rca outlet on the backof the headunit... through the pass through outlets on one amp to the other... or with a y adapter to each one thanks in advance

[Fixxxer]

ok im running two amps, one for each sub how do i connect them both to the rca outlet on the backof the headunit... through the pass through outlets on one amp to the other... or with a y adapter to each one thanks in advance

Hey there,

You can do it both ways as you stated in your post.

If you have output RCA's from your amp then just use those, but its just as easy to get some splitters. The signal will be exactly the same.

Fixxxer

[mr 32]

i would use the rca output on the amp before using splitters

[RANDY]

Splitters will split the very low voltage you have running through the RCA's. The amp passthrough should filter/amp the signal back up to where it should be. Never use splitters unless you really have to!

[jantolis]

Splitters will actually half the pre out signal strength aswell won't they?? Meaning you need to turn your amp up more.

[RANDY]

I beleive it would halve it, yes, that's what I meant. It gives more chance of noise to be introduced, but since the split will be fairly near the end, it might not cause any issues. Cheaper and better to use the 1st amp's passthrough for the 2nd amp.

[Bliksem]

Use the pass through outlets on the amp, wont sacrafice signal strenth then

[jantolis]

Yeah if the passthrough is there use it. It's easily the best option.

In my car i had to use a splitter for the sub output because i accidently stuffed up one of the rca outputs by running 12v through it and for some reason i hear a thumping everytime i turn car on/off or change tracks or radio stations. Very annoying.

Well when i split it, the amp needed to be turned up alot more, but it could handle it. A cheap splitter is around $1 from jaycar so not very expensive.

[fr0st]

haha, splitters don't halve the signal :laughing-smiley-014:

Amplifiers draw something like microamps from the signal line, its nothing that could cause any signal loss. Your main worry should be noise when running the cable. Longer cables pick up more noise and you lose a little signal to resistance. Never run RCA's next to the power cable aswell, they produce alot of noise and grounding problems.

Turn on thump is most likely a grounding issue btw

[jantolis]

haha, splitters don't halve the signal :laughing-smiley-014:

Yeah it's not actually signal lose your right but it is half the power. So the waveform going in is actually half the size of the non split one.

[Space Goat]

In my car i had to use a splitter for the sub output because i accidently stuffed up one of the rca outputs by running 12v through it and for some reason i hear a thumping everytime i turn car on/off or change tracks or radio stations. Very annoying.

my head unit has done that since new... ive had it in for repair and they reakoned there was nothing wrong with it... (pioneer DEHP736) all i did to stop it was put a rocker switch on the remote wire... i turned it on and off before i turned the car off and after i switched it on or change radio stations ect... its a good thing to have if some nice policeman hears you music you can flick a switch and turn just the subs off until he passes

on the rca note thanks all for your help i will definately be using the passthrough

[fr0st]

Yeah it's not actually signal lose your right but it is half the power. So the waveform going in is actually half the size of the non split one.

Thats not right :

Think about it like two resistors in parallel. Each resistor represents the input impedance of an amplifier (typically >10k ohms). One side of the resistor is grounded, the other is the RCA connection. If we ignore the slight resistance of the cable between the two amplifiers (its less than 1 ohm anyway) the resistors receive the exact same voltage. Current is split between the two... but thats irrelevant as amplifiers amplify the voltage at the input and not the current.

Signal loss can only really occur because the impedance has dropped at the amplifer side of the cable. So we have a 10k ohm impedance for one amp and a 5k ohm impedance for two (parallel resistors again). More current has to flow but accross a cable of say 50 ohms (exagerated) you only lose 0.1 of a volt for a 10v signal as opposed to 0.05 voltage for one amplifier.

In short, if your losing signal to RCA cables its probably a faulty cable or connector thats somehow making the resistance of the cable higher. Things like loose connectors, kinks in the cable, rubbing against metal and internal break from stretching will all cause it.

[frx026]

While this is a very technical discussion, and I do have to agree that using splitters is not ideal, I think we have all over looked one small factor.

IT WONT MATTER. Yep, that's right. It wont matter one little bit.

The quality of equipment needed and its associated price makes this argument pointless.

Let me put it this way, go to a retailer, buy $1500- $2000 of equipment, instal rca splitters in the system and the equipment will not be of good enough quality to produce a level of sound quality that would represent an audible difference to the end user.

In English - the gear would not be good enough to hear the difference

On the other hand, spend $25k - $30k and you are starting to get into equipment that would be good enough to provide an oppurtunity to hear the difference.

And as logic would have it, if you were to spend that amount of money you would be getting equipment that would not need splitters anyway.

I guess at this point I should also provide an alternative, if you must use rca splitters and think they will effect your "sound quality" ( you wont hear it anyway) go out and waste, er spend you money on some crystal line drivers. They will take all the noise away.

[jantolis]

Thats not right :

Think about it like two resistors in parallel. Each resistor represents the input impedance of an amplifier (typically >10k ohms). One side of the resistor is grounded, the other is the RCA connection. If we ignore the slight resistance of the cable between the two amplifiers (its less than 1 ohm anyway) the resistors receive the exact same voltage. Current is split between the two... but thats irrelevant as amplifiers amplify the voltage at the input and not the current.

Signal loss can only really occur because the impedance has dropped at the amplifer side of the cable. So we have a 10k ohm impedance for one amp and a 5k ohm impedance for two (parallel resistors again). More current has to flow but accross a cable of say 50 ohms (exagerated) you only lose 0.1 of a volt for a 10v signal as opposed to 0.05 voltage for one amplifier.

In short, if your losing signal to RCA cables its probably a faulty cable or connector thats somehow making the resistance of the cable higher. Things like loose connectors, kinks in the cable, rubbing against metal and internal break from stretching will all cause it.

I stand corrected. I was thinking about the current which doesn't really matter in this case.

Funny that because i did a whole yearly subject on op-amps and did soooo many equations with them and actually designed one at uni. Well thats what happens when you don't look over things for a year.

Thankyou for correcting me

[fr0st]

I stand corrected. I was thinking about the current which doesn't really matter in this case.

Funny that because i did a whole yearly subject on op-amps and did soooo many equations with them and actually designed one at uni. Well thats what happens when you don't look over things for a year.

Thankyou for correcting me

No problems

frx026, I see the point your trying to make but splitters are actually the better option compared to pass throughs and line drivers. The signal remains shielded the entire time and isn't run through any components with noise of there own (e.g opamps) in a splitter. If it goes into an amplifier unsheilded (onto the board) with a switch mode power supply nearby and goes through an opamp and out again its going to pick up alot more noise than with a simple splitter.

That said, even if you spent 25k on audio gear I dout you'd hear the difference between a passthrough and splitter anyway. Its a limitation of our ears if anything.

As long as you don't buy absolute shit cable, you'll never have a problem. Any car audio salesman that tries to sell you oxygen free, quadruple shielded, snake-oil-included RCA's is just plain full of crap.