Head Unit/ RCA dilemma

[themastert 10+ year member]

My Pioneer head unit (DEHP3100UB) has 2 sets of RCA's. However one set is used for my amplifier powering my subs. I have that variable preamp setting in my head unit so that I can use those RCA's as a subwoofer preamp instead of a regular 4 channel preamp. Well now I want to hook up more amps to my head unit but I don't know how to go about doing that.

On a separate note, can I splice the control wire of one amp into the other?

Do I have to run a separate ground for the second amp or can I piggyback it into the other amp's ground?

I am going for vintage sound so I have 2 Blaupunkt amps from 1987 and I have very little knowledge on them. I do know they work as they were tested. The one I am currently attempting to hook up is the BPA-2120b.

Thank you so much for your time,

Themastert

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[daboyfrumdabx 10+ year member]

Switch the setting to "rear" and juse use y splitters to run that rear signal to your rear channel amp and the sub amp. Then leave the front preouts for the front front speakers.

Control wire. You're talking about the remote turn on? If so, yes.

Each amp will need it's own dedicated ground wire. you can pick up a distribution block and run each ground wire to it, then a larger wire from the block to ground. Or just run each wire straight to ground, but you can not "piggyback" your ground wires.

 

[Side Show 10+ year member]

I Run ground for each amp, being sure to remove paint to ensure the best connection. if you have two sets of rca's you can run one set to your sub amp (LPF) And the other rca's to your speakers amp (HPF), and yes you can split the rca's to run more amps.

 

[themastert 10+ year member]

Ok well I tried using y splitters but I think I need to change the head units preouts as suggested. Not totally sure on that one, gotta consult the owners manual. I did splice the control wires together, works perfectly. I also ran a separate ground, it's taped for now till I get a self tapping screw in there. I wanted a distribution block but I only have one, and its on the positive end from the battery. My head unit actually has two sets of RCA's but I don't know how to designate one for the subs and the other for the rears. It's meant for a 4 channel...

Thanks again

 

[akheathen Premium Member]

do the blau have pass-through, or other out? if the amps are both being used as sub drivers, then you can leave the head set to sub, and split, or run-through the rca's. if it is going to be setup for sub and mids/highs off the same rca signal, then you can set the deck to full, or "rear" and use the amplifier settings, or an active cross-over to split the channels......which there are a bunch of options for active cross-overs, keeping in the vintage spirit

 

[themastert 10+ year member]

no the blau has nothing out other than these nice little spring loaded speaker outputs. Well that and 8 pin DIN socket which I actually have the wires for but I won't even get into that. One amp is being used as a sub driver, the other is powering the rear speakers. So in my case, I probably shouldn't be splitting the RCA signal. What amplifier settings are you talking about? I have crossovers, the original 1987 blau ones and some other sets but they all seem to operate in the same fashion as the blau. you just put the speaker wire in different terminals to adjust the crossover. Is that active?

 

[azphat12 10+ year member]

He meant an electronic crossover that you would hook up like your amps. Power/ground/remote to the crossover. You could then run 2 sets of RCA's to the crossover / or just 1. And let the electronic crossover be your RCA splitter so to speak.

http://www.audiocontrol.com/t34/5251/18487/Car-Audio-Electronic-Crossovers/6XS-6-Channel-Electronic-Crossover.html

This would probably work. Have your RCA from the head unit go into this. Then out of this to your amps. It is 2 or 3 way capable.

I should note. If you do one of these you would set your head unit to front/rear. Just a normal signal. The crossover will can be setup to distribute the sound properly.

 

[themastert 10+ year member]

Is there any way around this without spending additional money. I talked to the installer at Best Buy, and he said he could do it... for a ridiculous cost. He didn't mention anything about a crossover... I would also like the experience myself, I'm big on home audio but car audio is still a bit new to me.

 

[daboyfrumdabx 10+ year member]

Should work the way I said.

Head unit front preouts->channels 1&2 of 4 channel

head unit rear preouts(set to "rear")->y splitters->Channels 3&4 of 4 channel AND to your sub amp. The voltage getting to those rear channels and the sub amp will be lower, meaning you'll have to turn the gain a bit higher to compensate, but it should work. The best thing to do is pick up a new HU with 6 channel preouts or pick up a crossover of sorts as mentioned, but this should work.

 

[themastert 10+ year member]

Alright I will try this out. Basically I just need SOMETHING by tomorrow, it'll be my birthday and I received 1987 Blau amps, crossovers, woofers, mid range drivers, tweeters, EQ, etc. I just want to have something to show for in terms of birthday gifts. Where I'm located its a few degrees below freezing and Im working out on the street with a flashlight in my mouth. This might wait till tomorrow. I will keep this post posted hahaha.

Thank you all for the help!!

Oh what do you mean by "Set to rear"

 

[themastert 10+ year member]

Oh here's another thing, I have speaker wire already there to all the speakers, can i just leave the front ones attached to the head unit? Obv. I have to run the rears from the amp.

 

[akheathen Premium Member]

yah, the cross-overs you have are called "passive" just like the cross-overs inside your 2,3,4-way speakers in your house. for taking one chanel and splitting the output to different frequency speakers. so, the sub amp doesn't have a low-pass switch/knob/screw to set, or adjust? if not, you will be playing full-range through your subs, which can damage them. if you cannot segregate the rca signal with the amps, perhaps you can invert the front/rear configuration. i'm assuming you are playing the fronts off the head, and powering the rears off the amp. you have different options without adding anything. you can simply run the rear speaker amp from the front rca's, if you want to keep fading, you can hook the front speakers to the rear speaker outputs from the deck. this way, you can leave the rear rca's set to sub, and the deck will not fade them, and the only problem, would be that front and rear on the deck would fade back-wards. the best thing, would simply to install an active cross-over.

 

[daboyfrumdabx 10+ year member]

Oh here's another thing, I have speaker wire already there to all the speakers, can i just leave the front ones attached to the head unit? Obv. I have to run the rears from the amp.

I believe you can change the setting for the second set of RCA outputs on your deck. I believe it can be set to "rear" or "subwoofer". If this is the case, set it to "rear", so that your 4 channel amp receives the proper signal for the rear speakers. Then on your sub amp, you'll just adjust the LPF(low pass frequency) to 85ish(somewhere around there) to cutout frequencies that should reach the amp. If you leave it set to "subwoofer", most of these frequencies are already cut out and they won't rear the 4 channel amp even though your rear speakers are capable of playing such frequencies.

 

[themastert 10+ year member]

I don't doubt that you can change them, actually the manual says you can, it just doesn't give a clear example on how to. Under subwoofer settings it says revers, normal, and off, is that where it is? other than that I wouldn't have a clue, I'm scrolling through every setting...

 

[daboyfrumdabx 10+ year member]

I don't doubt that you can change them, actually the manual says you can, it just doesn't give a clear example on how to. Under subwoofer settings it says revers, normal, and off, is that where it is? other than that I wouldn't have a clue, I'm scrolling through every setting...

I think that may actually be a low pass filter, built in(don't quote me on that though). If anything, I'd try setting it to "off". Maybe someone else more familiar with pioneer decks can clarify.